• Journal of Pharmaceutical Investigation
• /
• v.31 no.2
• /
• pp.113-117
• /
• 2001

CKD602, a camptothecin derivative, is a synthetic and water-soluble anticancer agent possessing of topoisomerase I inhibiting activity. DPPC and DSPE-PEG liposomal formulations entrapped with CKD602 were developed. DSPE-PEG liposome, or PEGylated liposome, encapsulating CKD602 composed of dipalmitoylphosphatidylcholine (DPPC), cholesterol and distearoyl-N-monoethoxy poly (ethyleneglycol) succinylphosphatidylethanolamine $(DSPE-PEG_{2000})$ (22:11:2) was prepared by reverse-phase evaporation method. Formed liposomes were characterized in terms of the morphology, size and encapsulation efficiency. To elucidate the in vitro stability, PEGylated liposome was incubated in human plasma, and the adsorbed proteins onto the surface of liposomes were applied to the SDS-PAGE. In vitro cytotoxicity of CKD602 encapsulated in PEGylated liposome was studied in human cervical cancer cell line (HeLa). CKD602 in PEGylated liposome was found to be 40-fold more effective $(IC_{50}=1\;nM)$ than free CKD602 $(IC_{50}=40\;nM)$ in inhibiting the growth of HeLa cells in vitro.

• Journal of Pharmaceutical Investigation
• /
• v.35 no.5
• /
• pp.337-341
• /
• 2005

The purpose of the study was to prepare the pegylated liposome carrying plasmid DNA with optimal encapsulation efficiency. Plasmid DNA (pCEP4 clone 790, 10.6 kb) was entrapped in the pegylated liposome composed of neutral lipid, POPC (l-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine), cationic lipid, DDAB (dimethyl dioctadecyl ammonium bromide) and anionic lipids, DSPE-PEG 2000 (distearoyl phosphatidyl ethanolamine polyethylene glycol 2000) and DSPE-PEG 2000-maleimide by freezing/thawing method. Free plasmid DNA was separated from the encapsulated one by Sepharose CL-4B column chromatography. The DNA amount encapsulated into the pegylated liposome was increased as cationic lipid concentration, initial amount of plasmid DNA and total lipid amount were increased.

• Proceedings of the PSK Conference
• /
• 2000.10a
• /
• pp.262.2-262.2
• /
• 2000

• Bulletin of the Korean Chemical Society
• /
• v.34 no.10
• /
• pp.3083-3087
• /
• 2013

Diacetylene lipid monomers possess the capability to self-assemble into vesicles via polymerization under ultraviolet irradiation, resulting in the formation of polydiacetylene (PDA) liposomes. Exposure of the polymerized vesicles to external stimuli is known to induce a unique blue-to-red color transition. The cyclic oligosaccharide ${\alpha}$-cyclodextrin known for its use in many applications, such as drug delivery, purification, and stimulus sensing, is able to form an inclusion complex with poly(ethylene glycol) (PEG) in aqueous solution. In this study, we prepared polymeric liposomes with PEG (PEG-PDA) with the aim of improving the stability of the vesicles and colorimetric response toward ${\alpha}$-cyclodextrin. We demonstrated that PEG-PDA liposome displays unique characteristics compared with native PDA liposome and it also shows apparent chromic properties of the inclusion complex formation with ${\alpha}$-cyclodextrin.

• Journal of Pharmaceutical Investigation
• /
• v.33 no.3
• /
• pp.209-213
• /
• 2003

The objective of this study was to construct the pegylated liposomes containing plasmid DNA with optimal encapsulation efficiency. Plasmid DNA $(pGL2\;clone\;753,\;{\sim}6\;kb)$ was encapsulated by the freeze/thawing method into liposomes composed of 1-palmitoyl-2-oleyl-sn-glycerol-3-phosphocholine (POPC), didodecyl dimethyl ammonium bromide (DDAB), distearoylphosphatidyl ethanolamine polyethylene glycol 2000 (DSPE-PEG 2000) and DSPE-PEG 2000-male-imide. The liposomes containing plasmid DNA were then extruded through two stacked polycarbonate filters with series of different pore sizes to control the liposome size. The plasmid DNA entrapped in the liposomes was separated from free plasmid DNA by Sephadex CL-4B column chromatography. The decreased pore size of polycarbonate filters resulted in the decreased size of liposomes. The encapsulation efficiency was markedly affected by the cationic lipid (DDAB) concentration, but to a low degree by the size of liposomes and by the amount of plasmid DNA.